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Abstract:

A rigging table and methods and systems for assembling trusses using a
rigging table. An embodiment of a rigging table includes a base having a
generally longitudinal axis and a generally lateral extent, and at least
two bunk assemblies movable along the base in at least the generally
longitudinal axis such that each bunk assembly is capable of being
positioned on the base relative to another bunk assembly. Each bunk
assembly may include a frame extending along the lateral extent of the
base, a pair of guides slideably positioned on the frame to move
generally transverse to the longitudinal axis of the base toward and away
from each other and able to be fastened in position on the frame, and a
pair of automated clamp members each positioned relative to and movable
with one of the guides on the frame, to accommodate assembly of different
sized trusses.

Claims:

1. A rigging table for assembling trusses comprising:a base having a
generally longitudinal axis and a generally lateral extent;at least two
bunk assemblies movable along the base in at least the generally
longitudinal axis, each bunk assembly capable of being positioned on the
base relative to another bunk assembly;each bunk assembly comprising:a
frame extending along the lateral extent of the base;a pair of guides
slideably positioned on the frame to move generally transverse to the
longitudinal axis of the base toward and away from each other and able to
be fastened in position on the frame to accommodate assembly of different
sized trusses; anda pair of automated clamp members each positioned
relative to and movable with one of the guides on the frame to
accommodate assembly of different sized trusses, each clamp member
capable of securing an intersection of a chord and one or more webs to
facilitate assembly of a truss.

2. The rigging table as claimed in claim 1, where each guide is capable of
being indexed along the frame in predetermined increments adapted to
assemble different sized trusses, and fastened to the frame to facilitate
assembly of a truss.

3. The rigging table as claimed in claim 1, where each guide is capable of
alternatively being slidable along the frame and fastened in position to
facilitate assembly of different size trusses, or being indexed along the
frame in predetermined increments adapted to assembly of different sized
trusses and fastened to the frame to facilitate assembly of a truss.

4. The rigging table claimed in claim 1 where the at least two bunk
assemblies have clamp members each comprising:a stop portion capable of
positioning a chord and one or more webs during assembly of a truss; anda
clamp arm having an operative position capable of securing the chord and
one or more webs in relation to the stop portion for assembly of the
truss, and retracting after the truss is assembled.

5. The rigging table as claimed in claim 4 where at least two bunk
assemblies have clamp members each further comprising an actuator capable
of moving the clamp arm to secure the chord and one or more webs during
assembly of a truss, and retracting the clamp arm after the truss is
assembled.

6. The rigging table as claimed in claim 5 where each actuator
comprises:two actuating cylinders capable of being extended and
retracted; anda chain connected between the two actuating cylinders about
a sprocket such that the clamp arm is driven by the sprocket to move
between the securing and retracting positions.

7. The rigging table as claimed in claim 6 where each actuator comprises a
mechanism selected from the group consisting of a servo mechanism, a
hydraulic mechanism, and a pneumatic mechanism, and is capable of driving
the clamp arm between the securing and retracting positions.

8. The rigging table as claimed in claim 5 where each actuator comprises a
rack and pinion capable of driving the clamp arm between securing and
retracting positions.

9. The rigging table as claimed in claim 4 where each stop portion
comprises a nesting portion capable of positioning a chord portion of a
truss during assembly.

10. The rigging table as claimed in claim 9 where the nesting portion of
each stop portion is formed by an inner block and an outer block enabling
the chord portion to be positioned there between.

11. The rigging table as claimed in claim 1 further comprising at a least
one release member capable of disengaging an assembled truss from the
clamp members.

12. The rigging table as claimed in claim 11 where a release member is
attached to each frame of each bunk assembly.

13. The rigging table as claimed in claim 1 further comprising:rollers
capable of allowing assembled trusses to move generally longitudinally
along the base; andat least one tilt arm capable of moving an assembled
truss onto the rollers.

14. The rigging table as claimed in claim 13 where at least one roller is
attached to each frame of each bunk assembly.

15. The rigging table as claimed in claim 1 where the base has rails
extending along the generally longitudinal axis and capable of supporting
at least two bunk assemblies on a plurality of guide wheels attached to
the frames of the bunk assemblies, and capable of allowing the bunk
assemblies to move on the rails and be positioned to accommodate assembly
of different size trusses.

16. The rigging table as claimed in claim 1 where the base further
comprises stops adjacent each lateral extent of the base capable of
selectively engaging at least a portion of the frame such that when the
frame is positioned relative to the stops adjacent one lateral extent, a
zero camber is provided in the assembled truss, and when the frame is
positioned relative the stops adjacent the opposite lateral extent, a
standard camber is provided in the assembled truss.

17. The rigging table as claimed in claim 1 further comprising:conveyors
capable of moving chord portions, selected for a given truss to be
assembled, into position under the bunk assemblies adjacent the lateral
extent of the frames thereof; andautomated arms operative to engage a
chord portion positioned under the bunk assemblies and move the chord
portion to enable positioning the chord portion relative to the frame and
guides for assembly of a truss.

18. The rigging table as claimed in claim 1 further including an automated
worker guard panel capable of moving to enable the chord portion to be
moved from beneath the bunk assemblies to above the bunk assemblies for
positioning for assembly of a truss, and moving back to facilitate
movement of workers adjacent the lateral extent of the base.

19. A bunk assembly for a rigging table comprising:a frame extending along
a longitudinal extent and a lateral extent;a pair of guides slideably
positioned on the frame to move generally along the lateral extent toward
and away from each other and able to be fastened in position on the frame
to accommodate assembly of different size trusses; anda pair of automated
clamp members each positioned relative to and movable with one of the
guides on the frame to accommodate assembly of different sized trusses,
each clamp member capable of securing an intersection of a chord and one
or more webs to facilitate assembly of a truss.

20. The bunk assembly as claimed in claim 19 where each guide is capable
of being indexed along the frame in predetermined increments adapted to
assemble different sized trusses, and fastened to the frame to facilitate
assembly of a truss.

21. The bunk assembly as claimed in claim 19 where each guide is capable
of alternatively being slidable along the frame and fastened in position
to facilitate assembly of different size trusses, or being indexed along
the frame in predetermined increments adapted to assembly of different
sized trusses and fastened to the frame to facilitate assembly of a
truss.

22. The bunk assembly claimed in claim 19 where each clamp member
comprises:a stop portion capable of positioning a chord and one or more
webs during assembly of a truss; anda clamp arm having an operative
position capable of securing a chord and one or more webs in relation to
the stop portion for assembly of the truss, and retracting after the
truss is assembled.

23. The bunk assembly as claimed in claim 22 where each clamp member
further comprises an actuator capable of moving the clamp arm to secure
the components during assembly of a truss and retracting the clamp arm
after the truss is assembled.

24. The bunk assembly as claimed in claim 23 where each actuator
comprises:two actuating cylinders capable of being extended and
retracted;a chain connected between the two actuating cylinders about a
sprocket such that the clamp arm is driven by the sprocket to move
between the securing and retracting positions.

25. The bunk assembly as claimed in claim 24 where each actuator comprises
a mechanism selected from the group consisting of a servo mechanism, a
hydraulic mechanism, and a pneumatic mechanism, and is capable of driving
the clamp arm between the securing and retracting positions.

26. The bunk assembly as claimed in claim 24 where each actuator comprises
a rack and pinion capable of driving the clamp arm between the securing
and retracting positions.

27. The bunk assembly as claimed in claim 22 where each stop portion
comprisesa nesting portion capable of positioning a chord portion of a
truss during assembly.

28. The bunk assembly as claimed in claim 27 where the nesting portion of
each stop portion is formed by an inner block and an outer block enabling
a chord portion to be positioned there between.

29. The bunk assembly as claimed in claim 19 further comprising at least
one release member capable of disengaging an assembled truss from the
clamp members.

30. The bunk assembly as claimed in claim 29 where the at least one
release member is attached to the frame of the bunk assembly.

31. The bunk assembly as claimed in claim 19 further comprising:rollers
capable of allowing assembled trusses to move generally longitudinally
along a base of the rigging table; andat least one tilt arm capable of
moving an assembled truss onto the rollers.

32. The bunk assembly as claimed in claim 31 where at least one roller is
attached to the frame of the bunk assembly.

33. The bunk assembly as claimed in claim 19 further comprising a
plurality of guide wheels attached to the frame and capable of allowing
the bunk assembly to move on rails and be positioned to accommodate
assembly of different sized trusses.

34. The bunk assembly as claimed in claim 19, further comprising stops for
the guides on each lateral extent of the bunk assembly such that when the
guides are positioned relative to the stops from one side, a zero chamber
is provided in the assembled truss, and when the guides are positioned
relative the stops at the opposite side, a standard chamber is provided
in the assembled truss.

35. A method of assembling truss elements on a rigging table
comprising:assembling at least two bunk assemblies for a rigging table,
each bunk assembly comprising:a frame extending along a lateral extent
and a longitudinal extent;a pair of guides slideably positioned on the
frame to move generally along the lateral extent toward and away from
each other and able to be fastened in position on the frame to
accommodate assembly of different sized trusses; anda pair of automated
clamp members each positioned relative to and movable with one of the
guides on the frame to accommodate assembly of different sized trusses,
each clamp member capable of securing an intersection of a chord and one
or more webs to facilitate assembly of a truss;positioning each bunk
assembly on the rigging table in desired relation to another bunk
assembly to assemble trusses of a desired size;positioning clamp members
along the guides on each bunk assembly in desired relation to the other
clamp member to assemble trusses of the desired size; andpositioning
chords and webs of a truss and actuating the clamp members to hold the
chords and webs in desired location to assemble a truss of the desired
size.

36. The method of claim 35, comprising the further step of securing chords
and webs of a truss using a clamp arm in relation to a stop portion
during assembly of a truss.

37. The method of claim 36, comprising the further step of tack-welding
the chords and webs together to assemble a truss.

38. The method of claim 37, comprising the further step of lifting the
tack-welded truss upward above the bunk assemblies.

Description:

BACKGROUND AND SUMMARY

[0001]The present invention relates to rigging tables, and to methods and
systems for assembling trusses using a rigging table.

[0002]Various processes and techniques have been used to manually
fabricate steel open-web trusses. Such fabrication techniques may involve
processes including cut-out, rigging, welding, inspection, and painting
operations. The welding operation can be the bottleneck or rate-limiting
operation limiting production capacity. In a cut-out operation, steel
angle and rod chord and web components are cut to length with hydraulic
shears, cut-off dies, hydraulic presses, or other cutting devices. The
cut-out operation may further include shaping the end of the web
components to form a desired shape and size. In a rigging operation,
assembly workers, or riggers, arrange the sized components in proper
position and clamp and tack-weld the components in place. In a welding
operation, a team of welders apply structural welds at component
connections to give the truss strength. In an inspection operation, an
inspector verifies material sizes, component lengths, welds, and
positions. In a painting operation, a truss is dipped in a tank of
coating material, such as a water-based primer, drained of excess primer,
dried, and then loaded onto a transport out of the plant.

[0003]An assembly table or rigging table may be used, which includes
fixtures for positioning the chord and web components in position while
the components are clamped and tack-welded together. The long (e.g., up
to 65 feet) structural components at the top and bottom of the trusses
are known as chords. Chords may be supplied from a position behind the
riggers on either side of the rigging table. In the past, the riggers had
to turn away from the table, work together to lift a chord overhead, turn
back toward the table while holding the chord, and lower the chord into
the appropriate fixtures on the table. Once the riggers added the shorter
web components, or webs, to the chord portion on the table, a second
chord portion may be added. The components were then clamped and tack
welded together. In the past, the riggers typically used hand clamps for
this purpose. The riggers then send the rigged truss to the welding area
on transfer rollers.

[0004]Manual lifting of the chords can be inefficient. When lifting heavy
chords overhead, the riggers take time and precautions to handle the
chords safely. Manual hand clamping of truss components is also
inefficient, requiring hand strength and operator judgment as to
placement.

[0005]What has been needed is a rigging table that automates assembly of
trusses of different sizes and allows easy adjustability.

[0006]A rigging table is presently disclosed for assembling trusses
comprising: [0007]a) a base having a generally longitudinal axis and a
generally lateral extent; [0008]b) at least two bunk assemblies movable
along the base in at least the generally longitudinal axis, each bunk
assembly capable of being positioned on the base relative to another bunk
assembly; [0009]c) each bunk assembly comprising: [0010]a frame
extending along the lateral extent of the base; [0011]a pair of guides
slideably positioned on the frame to move generally transverse to the
longitudinal axis of the base toward and away from each other and able to
be fastened in position on the frame to accommodate assembly of different
sized trusses; and [0012]a pair of automated clamp members each
positioned relative to and movable with one of the guides on the frame to
accommodate assembly of different sized trusses, each clamp member
capable of securing an intersection of a chord and one or more webs to
facilitate assembly of a truss.

[0013]The guides may be capable of being indexed along the frame in
predetermined increments adapted to assembly of different sized trusses
and fastened to the frame to facilitate assembly of a truss. As an
alternate, each guide may be capable of alternatively being slidable
along the frame and fastened in position to facilitate assembly of
different size trusses, or being indexed along the frame in predetermined
increments adapted to assembly of different sized trusses and fastened to
the frame to facilitate assembly of a truss.

[0014]Each bunk assembly may have clamp members each comprising: [0015]a
stop portion capable of positioning a chord and one or more webs during
assembly of a truss; and [0016]a clamp arm having an operative position
capable of securing the chords and one or more webs in relation to the
stop portion for assembly of the truss, and retracting after the truss is
assembled.

[0017]Each clamp member may further comprise an actuator capable of moving
the clamp arm to secure the chord and one or more webs during assembly of
a truss and retracting the clamp arm after the truss is assembled. Each
actuator may include a mechanism selected from the group consisting of a
servo mechanism, a hydraulic mechanism, and a pneumatic mechanism, and is
capable of driving the clamp arm between the securing and retracting
positions. Each actuator may, for example, include two actuating
cylinders capable of being extended and retracted, and a chain connected
between the two actuating cylinders about a sprocket such that the clamp
arm is driven by the sprocket to move between the securing and retracting
positions. Alternatively, each actuator may include a rack and pinion
capable of driving the clamp arm between securing and retracting
positions.

[0018]Each stop portion may include a nesting portion capable of
positioning a chord portion of a truss during assembly. The nesting
portion of each stop portion may be formed by an inner block and an outer
block enabling the chord portion to be positioned there between.

[0019]The rigging table may further include at least one release member
capable of disengaging an assembled truss from the clamp members. A
release member may be attached to each frame of each bunk assembly.

[0020]A bunk assembly may include rollers capable of allowing assembled
trusses to move generally longitudinally along the base, and at least one
tilt arm capable of moving an assembled truss onto the rollers. Each
roller may be attached to each frame of each bunk assembly.

[0021]The base of the rigging table may include rails extending along the
generally longitudinal axis and are capable of supporting at least two
bunk assemblies on a plurality of guide wheels, for example, attached to
the frames of the bunk assemblies. The base rails are capable of allowing
the bunk assemblies to move on the rails and be positioned to accommodate
assembly of different size trusses.

[0022]The base of the rigging table may also include stops adjacent each
lateral extent of the base, capable of selectively engaging at least a
portion of the frame such that when the frame is positioned relative to
the stops adjacent one lateral extent, a zero camber is provided in the
assembled truss, and when the frame is positioned relative the stops
adjacent the opposite lateral extent, a standard camber is provided in
the assembled truss.

[0023]The rigging table may also include conveyors capable of moving chord
portions, selected for a given truss to be assembled, into position under
the bunk assemblies adjacent the lateral extent of the frames thereof.
The rigging table may further include automated arms operative to engage
a chord portion positioned under the bunk assemblies and move the chord
portion to enable positioning the chord portion relative to the frame and
guides for assembly of a truss. The rigging table may include an
automated worker guard panel that is capable of moving to enable the
chord portion to be moved from beneath the bunk assemblies to above the
bunk assemblies for positioning for assembly of a truss, and moving back
to facilitate movement of workers adjacent the lateral extent of the
base.

[0024]A bunk assembly is disclosed for a rigging table comprising:
[0025]a) a frame extending along a longitudinal extent and a lateral
extent; [0026]b) a pair of guides slideably positioned on the frame to
move generally along the lateral extent toward and away from each other
and able to be fastened in position on the frame to accommodate assembly
of different size trusses; and [0027]c) a pair of automated clamp members
each positioned relative to and movable with one of the guides on the
frame to accommodate assembly of different sized trusses, each clamp
member capable of securing an intersection of a chord and one or more
webs to facilitate assembly of a truss.

[0028]The guides may be capable of being indexed along the frame in
predetermined increments adapted to assembly of different sized trusses
and fastened to the frame to facilitate assembly of a truss. Alternately,
each guide of the bunk assembly may be capable of alternately being
slideable along the frame and fastened in position to facilitate assembly
of different size trusses, or being indexed along the frame in
predetermined increments adapted to assembly of different sized trusses
and fastened to the frame to facilitate assembly of a truss.

[0029]Each clamp member of the bunk assembly may include a stop portion
capable of positioning a chord and one or more webs during assembly of a
truss, and a clamp arm having an operative position capable of securing a
chord and one or more webs in relation to the stop portion for assembly
of the truss, and retracting after the truss is assembled. Each clamp
member may include an actuator capable of moving the clamp arm to secure
the components during assembly of a truss and retracting the clamp arm
after the truss is assembled.

[0030]Each actuator may include a mechanism selected from the group
consisting of a servo mechanism, a hydraulic mechanism, and a pneumatic
mechanism, capable of driving the clamp arm between the securing and
retracting positions. Each actuator may include, for example, two
actuating cylinders capable of being extended and retracted, and a chain
connected between the two actuating cylinders about a sprocket such that
the clamp arm is driven by the sprocket to move between the securing and
retracting positions. Alternatively, each actuator may include a rack and
pinion capable of driving the clamp arm between the securing and
retracting positions.

[0031]Each stop portion may include a nesting portion capable of
positioning a chord portion of a truss during assembly. The nesting
portion of each stop portion may be formed by an inner block and an outer
block enabling a chord portion to be positioned there between.

[0032]The bunk assembly may include at least one release member capable of
disengaging an assembled truss from the clamp members. The release member
may be attached to the frame of the bunk assembly.

[0033]The bunk assembly may further include rollers capable of allowing
assembled trusses to move generally longitudinally along a base of the
rigging table, and at least one tilt arm capable of moving an assembled
truss onto the rollers. At least one roller may be attached to the frame
of the bunk assembly. The bunk assembly may include a plurality of guide
wheels attached to the frame and capable of allowing the bunk assembly to
move on rails and be positioned to accommodate assembly of different
sized trusses.

[0034]The bunk assembly may further include stops for the guides, on each
lateral extent of the bunk assembly, such that when the guides are
positioned relative to the stops from one side, a zero camber is provided
in the assembled truss, and when the guides are positioned relative to
the stops at the opposite side, a standard camber is provided in the
assembled truss.

[0035]A method is disclosed of assembling truss elements on a rigging
table comprising: [0036]a) assembling at least two bunk assemblies for
a rigging table with each bunk assembly comprising a frame extending
along a lateral extent and a longitudinal extent, a pair of guides
slideably positioned on the frame to move generally along the lateral
extent toward and away from each other and able to be fastened in
position on the frame to accommodate assembly of different sized trusses,
and a pair of automated clamp members each positioned relative to an
movable with one of the guides on the frame to accommodate assembly of
different sized trusses, each clamp member capable of securing an
intersection of a chord and one or more webs to facilitate assembly of a
truss; [0037]b) positioning each bunk assembly along the rigging table in
desired relation to another bunk assembly to assemble trusses of a
desired size; [0038]c) positioning clamp members along the guides on each
bunk assembly in desired relation to the other clamp members to assemble
trusses of the desired size; and [0039]d) positioning chords and webs of
a truss and actuating the clamp members to hold the chords and webs is
desired location to assemble a truss of the desired size.

[0040]The method may further include securing chords and webs of a truss
using a clamp arm in relation to a stop portion during assembly of a
truss, and at least tack-welding the chords and webs together to assemble
a truss. The method may further include the further step of lifting the
tack-welded truss upward above the bunk assemblies.

[0041]These and other advantages and novel features, as well as details of
illustrated embodiments thereof, will be more fully understood from the
following description and drawings. Further disadvantages of
conventional, traditional, and proposed approaches will become apparent
to one of skill in the art, from a description of embodiments of the
systems and methods as set forth in the remainder of the present
application with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042]FIG. 1 is a diagrammatical plan view of a bunk assembly used in
assembling trusses on a rigging table having a pair of clamp members on
guides;

[0043]FIG. 2 is a partial perspective view of an alternate bunk assembly
to the bunk assembly of FIG. 1 showing one clamp member with a chain
guard removed and the second clamp member removed from the bunk assembly;

[0044]FIG. 3 is a second partial perspective view of the clamp member of
the alternate bunk assembly shown in FIG. 2;

[0045]FIG. 4 is a partial perspective view of the clamp arm of FIG. 3
being in a securing position to secure a web between two chord portions
during assembly of a truss;

[0046]FIG. 5A is a partial plan view of a clamp member of the bunk
assembly of FIG. 1;

[0047]FIG. 5B is a view of the clamp member of FIG. 5A with the chain
guard removed;

[0048]FIG. 6A is a side view of the clamp member of FIG. 5B in a retracted
position;

[0049]FIG. 6B is a side view of the clamp member of FIG. 5B in a securing
position;

[0050]FIG. 7 is a partial section view through the bunk assembly of FIG. 1
through the section marked 7-7 showing a friction lock in a loosened
position;

[0051]FIG. 8 is an end view of the bunk assembly of FIG. 1 positioned on a
base of a rigging table;

[0052]FIG. 9 is a diagrammatical plan view of a second alternate bunk
assembly having a tilt arm for lifting a tack-welded truss upward and
onto rollers of other standard bunk assemblies;

[0053]FIG. 10 is an end view of the bunk assembly of FIG. 9 with a raised
tilt arm;

[0054]FIG. 11 is a diagrammatical plan view showing two of a third
alternate bunk assembly each having one clamp member on a guide;

[0055]FIG. 12 is a diagrammatical plan view of a rigging table and
associated chord portion conveyors for use in assembling trusses;

[0056]FIG. 13 is a diagrammatical side view of a portion of a rigging
table illustrating the relationship between a chord portion conveyor,
guard panel, and chord portion lifting arms;

[0057]FIG. 14A is a schematic diagram of an end view of a portion of the
rigging table of FIG. 13 showing a chord portion resting on the chord
portion conveyor with the guard panel in a closed position;

[0058]FIG. 14B is a schematic diagram of an end view of a portion of the
rigging table of FIG. 13 showing a chord portion lifted off of a chord
portion conveyor by automated lifting arms with the guard panels in an
open position;

[0059]FIG. 15 is a partial perspective view of a chord portion lifting arm
in an extended position for lifting a chord portion upward and off of a
chord portion conveyor with the guard panel in the closed position; and

[0060]FIG. 16 is a partial perspective front view of the chord portion
lifting arm in a retracted position before lifting a chord portion off of
a chord portion conveyor.

DETAILED DESCRIPTION OF THE DRAWINGS

[0061]A rigging table, for assembling trusses, that includes adjustable
bunk assemblies is disclosed. As used herein, the term "truss" means an
assembly of chords and webs (e.g., steel chords and webs) as generally
used in construction. Such an assembly of chords and webs is sometimes
also referred to as a joist or a girder.

[0062]FIGS. 1-11 illustrate various aspects of bunk assemblies 10 and 800
used as part of a rigging table in assembling trusses, in accordance with
an embodiment of the present invention. FIG. 1 illustrates an exemplary
embodiment of a bunk assembly 10 having a pair of automated clamp members
20 and used in assembling trusses on a rigging table. FIG. 2 illustrates
a first view of an exemplary embodiment of one automated clamp member 20
of the bunk assembly 10 of FIG. 1. FIG. 3 illustrates a second view of an
exemplary embodiment of one automated clamp member 20 of the bunk
assembly 10 of FIG. 1. FIG. 4 illustrates an exemplary embodiment of a
clamp arm 80 of one clamp member 20 of the bunk assembly 10 of FIG. 1
being in a securing position to secure webs 500 between two chord
portions 200 during assembly of a truss. Two chord portions 200 may be
used to make a single chord.

[0063]At least two bunk assemblies 10 may be used in a rigging table to
secure and establish lateral and longitudinal spatial relationships
between chord portions 200 and webs 500 of a truss to be assembled. The
bunk assembly 10 includes a frame 30 having an extent in a generally
lateral direction 40 relative to a base and an extent in a generally
longitudinal direction 50 relative to the base. The frame 30 includes an
outer frame portion 37 and an inner frame portion 33.

[0064]The bunk assembly 10 also includes a pair of guides 60 slideably
positioned on the frame 30 to move generally transverse to the
longitudinal axis of the base, or transverse to the longitudinal
direction 50, toward and away from each other (i.e., generally in the
lateral direction 40). The guides 60 are capable of being fastened in
position on the frame 30 to accommodate assembly of different sized
trusses. Each guide 60 is capable of being indexed along the frame 30 in
predetermined increments adapted to assembly of different sized trusses
of predetermined sizes, and fastened to the frame 30 to facilitate
assembly of a truss. Furthermore, each guide 60 may be capable of being
slidable along the frame and fastened in position between index positions
to facilitate assembly of different size trusses.

[0065]The automated clamp members 20 may each be positioned relative to
and movable with one of the guides 60 on the frame 30 to accommodate
assembly of different sized trusses. Each automated clamp member 20 is
capable of securing an intersection of at least one chord portion 200 and
one or more webs 500 to facilitate assembly of a truss. Furthermore, each
automated clamp member 20 includes a stop portion 70 capable of
positioning at least one chord portion 200 and one or more webs 500
during assembly of a truss. As shown in FIG. 3, each stop portion 70
includes an inner block 71 and an outer block 72 forming a nesting
portion 73 there between, enabling a chord portion 200 to be positioned
within the nesting portion 73.

[0066]As shown in FIGS. 2-4, each automated clamp member 20 includes a
clamp arm 80 having an operative position capable of securing at least
one chord portion 200 and one or more webs 500 in relation to the stop
portion 70 for assembly of a truss, and retracting after the truss is
assembled. Each automated clamp member 20 also includes an actuator 90
capable of moving the clamp arm 80 to secure at least one chord portion
200 and one or more webs 500 during assembly of a truss, and retracting
the clamp arm 80 after the truss is assembled.

[0067]Each actuator 90 may include two actuating cylinders 91 and 92
capable of being extended and retracted, and a chain 93 connected between
the two actuating cylinders 91 and 92 about a sprocket 94. The clamp arm
80 is driven by the sprocket 94 to move between the securing and the
retracting positions, as shown in FIGS. 6A and 6B. The chain and sprocket
may be covered by a chain guard. FIGS. 5B, 6A, and 6B show the assembly
with the chain guard removed. Each actuator 90 may include a servo
mechanism, a hydraulic mechanism, or a pneumatic mechanism that is
capable of driving the clamp arm 80 between the securing and the
retracting positions. As an alternative, each actuator 90 may include a
rack and pinion capable of driving the clamp arm 80 between the securing
and retracting positions.

[0068]A bunk assembly 10 may include at least one release member 100
capable of disengaging an assembled truss from the clamp members 20. The
release members 100 may be attached to the frame 30 of the bunk assembly
10 and are capable of being actuated upward to lift an assembled truss
out of and above the clamp members 20. Some bunk assemblies 10 may not
have a release member 100. The number of bunk assemblies 10 on the
rigging table 10 having at least one release member 100 may be determined
by the size and weight of the assembled truss and the lifting capacity of
each release member.

[0069]A bunk assembly 10 may include a roller 110 capable of allowing an
assembled truss to move generally longitudinally along the rigging table
10. The roller 110 is attached to the frame 30 of the bunk assembly and
is capable of being actuated upward such that an assembled truss rolling
along the roller 110 may clear the clamp members 20. Typically, a bunk
assembly 10 will have a roller 110 and at least one release member 100.
Certain other specialized bunk assemblies such as bunk assembly 800 may
not include a roller 110 or release members 100. Instead, certain other
specialized bunk assemblies 800 may include a tilt arm mechanism 810 as
shown and described later herein with respect to FIGS. 9 and 10.

[0070]FIG. 2 illustrates an exemplary embodiment of a track 400 including
a friction lock slot 410 and a track recess 420 as part of the inner
frame portion 33 of the frame 30. As shown in FIG. 7, a corresponding
runner, such as a protrusion or other feature, along the bottom of the
guide 60 is positioned within the track recess 420 enabling the guide to
move along the track in the lateral direction 40. By moving the guides 60
along the tracks 400, the clamp members 20 may be moved closer to each
other or further away from each other to establish a lateral extent of a
truss to be assembled. A friction lock 61 extending through the friction
lock slot 410 may be used to secure the guide 60 in a desired position.
As an example, the friction lock 61 may include a nut and bolt assembly
such that the friction lock 61 may be tightened or loosened within the
friction lock slot 410. The runner along the bottom of the guide 60 is
positioned within the track recess 420 and serves, along with the
friction lock 61 through the friction lock slot 410, to hold the guide 60
in place with respect to the frame 30. The guide 60 rests on the top
surfaces of the inner frame portion 33 of the frame 30, including side
rails 34 of the inner frame portion 33 and a central index rail 35 of the
inner frame portion 33 as shown in FIGS. 1 through 4.

[0071]The central index rail 35 may include a plurality of indexing
recesses, or teeth, capable of laterally positioning the guide 60 along
the frame. The teeth of the central index rail 35 are spaced in
predetermined increments, such as for example, one inch increments, or
two centimeter increments, or other spaced increments as desired. A
pop-lock 62, passing through or adjacent the guide 60, may be used to
index the guide 60 to the teeth of the central index rail 35. The guide
60 may be moved laterally along the frame 30 and track 400 when the
pop-lock 62 is released and the friction lock 61 is loosened. When placed
in a desired lateral position along the index rail 35, the pop-lock 62
may be locked between the teeth of the index rail 35 and the friction
lock 61 may be tightened to securely hold the guide 60 in place.
Alternatively, the guide 60 may be secured between two teeth positions by
tightening the friction lock 61 in the desired position with the pop-lock
62 remaining released.

[0072]As shown in FIG. 8, the bunk assembly 10 of FIG. 1 may be positioned
on a rigging table base 600. The base 600 may include two substantially
parallel rails 610 extending along the generally longitudinal direction
50 and capable of supporting at least two bunk assemblies 10 on a
plurality of guide wheels 31 attached to the frames 30 of the bunk
assemblies. The guide wheels 31 allow the bunk assemblies 10 to move on
the rails 610 and be positioned or spaced longitudinally with respect to
each other to accommodate assembly of different sized trusses. The wheels
31 along one rail 610 may be configured with a v-groove or other shape
adapted to engage a corresponding shape on the rail 610 as shown in FIGS.
1 and 8. The v-groove or other shape guide wheel 31 enables the wheel to
remain aligned with the rail 610. When the wheels 31 along one side of
the frame are adapted to engage a corresponding shape on the rail 610,
the wheels 31 on the other side of the frame may be capable of
accommodating variations in the distance between the rails 610 caused by
normal manufacturing tolerances, wear, environment, damage, or other
dimensional differences, such as by wheels having a smooth circumference
not engaging the rail.

[0073]The bunk assemblies 10 may be positioned with respect to each other
along the rails 610 to provide desired longitudinal distance or spacing
between clamp members 20 of adjacent bunk assemblies. The minimum
longitudinal distance between clamp members 20 of a plurality of bunk
assemblies may correspond to the width of the frame 30. When two adjacent
bunk assemblies 10 are butted against each other (bunk frames touching)
in the longitudinal direction 50, the distance from the clamp member of
one bunk assembly to the corresponding clamp member of the adjacent bunk
assembly may be about the width of the frame 30, which in the
configuration of FIG. 1 may be about thirty inches (about 0.75 meters).
Additionally, adjacent bunk assemblies 10 may be spaced apart as desired
during operation of the rigging table. Typically, the distance between
corresponding clamp members 20 from one bunk assembly to the next is
determined based on the structural design of the truss to be assembled,
and typically is less than about six feet (about 1.8 meters).

[0074]The bunk assemblies 10 may be capable of being slidable along the
rails 610 and fastened in position to facilitate assembly of different
size trusses. Further, the bunk assemblies may be capable of being
indexed along the base in predetermined increments to facilitate assembly
of desired trusses. The base 600 may include an indexing guide having a
plurality of indexing recesses, or teeth, capable of longitudinally
positioning the bunk assemblies along the base. An indexing guide may be
adjacent one or both of the rails 610, and may be integral with each
rail. The indexing teeth may be spaced in predetermined increments, such
as for example, one inch increments (about 2.5 centimeters), or two
centimeter increments (about 0.8 inch), or other spaced increments as
desired. As shown in FIG. 8, spring-loaded pop-pins 730 may be attached
to the frame 30 at each lateral extent such that the pop-pins 730 may
engage the indexing guide of the base 600 in order to locate a bunk
assembly 10 longitudinally along the base 600. The pop-pins 730 at each
lateral extent of the bunk assembly 10 may have release cables connected
together such that both pop-pins may be disengaged together by actuating
the connected release cable.

[0075]The inner portion 33 of the frame 30 is capable of being positioned
along the lateral direction 40 within the outer portion 37 of the frame
30. As best shown in FIG. 1, by loosening at least one friction lock 32,
the inner frame portion 33 is slidable within the outer frame portion 37
from one lateral extent to the other. The inner frame portion is
laterally positionable within the outer frame portion so that the inner
frame portion 33 and clamp members 20 along the base 600 can be
positioned to provide a desired camber along the length of the assembled
truss.

[0076]FIG. 8 illustrates a view of the bunk assembly 10 of FIG. 1
positioned on a base 600 of a rigging table. To assist in positioning the
plurality of clamp members to provide the desired camber, the base 600
may include longitudinally extending camber rails, or camber stops 710,
adjacent one or both lateral extents of the base 600 bounding the lateral
movement of the inner frame portion 33. A guide portion 720 of the inner
frame portion 33 is capable of selectively engaging the camber stops such
that the inner frame portion 33 may be positioned relative to or abutting
the camber stop 710 adjacent one lateral extent, or moved in the lateral
direction 40 toward a camber stop adjacent the opposite lateral extent.
When a camber stop is not provided along a lateral extent, the movement
of the inner frame portion 33 may be bounded by the outer frame portion
37 or the rail 610, or the base 600, any of which may be adapted to
provide zero camber in the assembled truss. Alternately, to provide zero
camber in the assembled truss, a straight camber stop may be provided to
align the inner frame portions with zero camber. The camber stops 710 may
be positioned adjacent to the rail 610, or may be integral to the rail.

[0077]The camber rails, or camber stops 710, may have an arcuate
longitudinal face along the base 600 such that a plurality of inner frame
portions 33 may be positioned relative to the arcuate face along the base
providing a camber corresponding to the arcuate radius. The camber stop
may be provided with a radius of curvature determined by an industry
standard, a structural design requirement, or other radius. While the
camber stops may have any desired radius of curvature, it is contemplated
that the rigging table be provided with a radius of curvature that is
typically assembled on the table, or a "standard camber." In one example,
the standard camber may be a radius of curvature of about 3,600 feet
(about 1097.3 meters). In the configuration of FIG. 8, the outer portion
37 of frame 30 provides the inner frame stop adjacent one lateral extent,
and a camber stop 710 is provided adjacent the opposite lateral extent.
In this embodiment, the plurality of bunk assemblies may be positioned
relative to or against the camber stop 710 during assembly of a truss to
provide assembled trusses having a slight curve, or camber corresponding
to the arcuate radius of the camber stop.

[0078]The friction lock 32 may include a nut and bolt assembly passing
through the outer portion 37 and inner portion 33 of the frame 30 capable
of securing the inner frame portion within the outer frame portion 37.
The friction lock 32 may be used to secure the inner portion 33 of the
frame 30 against either lateral extent bounded by the camber stop, the
rail 610, or the outer frame portion 37, to provide the desired camber.
Alternately, the friction lock 32 may be used to secure the inner frame
portion 33 positioned between the stops at the lateral extents to
provide, for example, a custom camber. When assembling a truss having a
defined camber, a center of a truss to be assembled may be aligned with
the center of the camber rail 710 to be able to assemble trusses of
different lengths having the same camber (i.e,. radius of curvature).
Furthermore, the camber rail 710 may be changed out with another camber
rail to accommodate the assembly of trusses having other radii of
curvature.

[0079]FIG. 9 illustrates an exemplary embodiment of a specialized bunk
assembly 800 having a tilt arm 810 for tilting a tack-welded truss upward
and onto the rollers 110 of standard bunk assemblies 10. FIG. 10
illustrates an exemplary embodiment of the tilt arm 810 of FIG. 9 in a
lifted position. Several specialized bunk assemblies 800 and tilt arms
810 may be positioned along the length of the base 600 of the rigging
table. After a truss is assembled (e.g., tack-welded) on the rigging
table, an operator may release all the clamp arms 80 via a single point
release. Alternately, operators may release each clamp arm 80 at each
bunk assembly 10. Then, the release members 100 within the standardized
bunk assemblies 10 are actuated to lift up the assembled truss to clear
the upper portion of the bunk assemblies 10, and the rollers 110 are
actuated to lift upward. The tilting arms 810 are then actuated to move
the assembled truss onto the rollers 110. The truss may be moved onto the
rollers in a generally vertical orientation. The tilting arms 810 may be
moved by actuator 820, which may be actuated hydraulically,
pneumatically, or by other actuators. The riggers at the rigging table
may assist in guiding the assembled truss onto the rollers 110 and then
move the truss along the table on the rollers. Once an assembled truss is
removed from the rigging table, the operators (riggers) may provide next
chord portions 200 and webs 500 to the bunk assemblies for assembly of
the next truss.

[0080]The tilt arm 810 may be attached to the frame 30 of the bunk
assembly 800 and is capable of being actuated such that a bottom portion
of the tilt arm 810 slides from one lateral extent of the bunk assembly
800 toward the opposite lateral extent of the bunk assembly 800 as the
tilt arm 810 operates. This enables the tilt arms 810 to lift an
assembled truss to a generally vertical position such that the assembled
truss rests on the rollers 110. The tilt arms 810 may include serrated
edges 811 to help catch the assembled truss as the assembled truss is
tilted upward. The assembled truss may then be rolled, in the
longitudinal direction 50, off of the rigging table by the rigging table
operators.

[0081]Other specialized bunk assemblies may be provided. Such other
specialized bunk assemblies may include end bunk assemblies that are
customized to assemble a certain type of end on each side of a truss.
Such end bunk assemblies may not have, for example, a roller 110 or a
tilt arm 810. Furthermore, such end bunk assemblies may include only one
clamp member 20, such as an end bunk assembly 850, 850' shown in FIG. 11,
and may be narrower (in the longitudinal direction 50) than the bunk
assembly 10 of FIG. 1. Other variations of end bunk assemblies are
possible as well, depending on the design of the end of the desired
truss.

[0082]The rigging table may include a material handling apparatus to
selectively position chord portions between the operators, or riggers,
and the rigging table to reduce the distance and motion needed to move
the chord portion to the clamp members 20. The material handling
apparatus may be capable of moving chord portions, selected for a given
truss to be assembled, into position under or below the bunk assemblies
adjacent the lateral extent of the frames 30, and having automated arms
operative to engage a chord portion positioned under or below the bunk
assemblies and move the chord portion to enable positioning of the chord
portion relative to the frame 30 and guides 60 for assembly of a truss.

[0083]FIG. 12 is a schematic diagram of a top view of an exemplary
embodiment of a rigging table 1000, having a generally longitudinal axis
51 in a generally longitudinal direction 50, and associated chord portion
conveyors 1010, 1020 and 1030 for use in assembling trusses. The various
bunk assemblies rest on top of the rails of the base 600 of the rigging
table 1000 as described previously herein.

[0084]As shown in FIG. 12, chord portions 200 are provided on a material
rack 1050. A chord portion 200 may be removed from the material rack
1050, by operators or by a removal device, and onto the first
longitudinal conveyor 1010 which is offset from the base 600 of the
rigging table 1000. The chord portion 200 travels down the first
longitudinal conveyor 1010 in the longitudinal direction 50 toward a
kickoff position 1060 where the chord portion 200 is kicked off of the
first longitudinal conveyor 1010 and onto a lateral conveyor 1020. In
this manner, chord portions 200 are queued along the lateral conveyor
1020. When a chord portion 200 is needed, the chord portion 200 transfers
from the lateral conveyor 1020 to a second longitudinal conveyor 1030. As
shown in FIG. 12, the second longitudinal conveyor 1030 may be positioned
adjacent the end of the lateral conveyor 1020, and the chord portions may
transfer from the lateral conveyor 1020 to the second longitudinal
conveyor 1030 by dropping from the lateral conveyor onto the second
longitudinal conveyor. Alternately, a kick-off arm may be used to kick
the chord portion 200 from the lateral conveyor 1020 to the second
longitudinal conveyor 1030. The first longitudinal conveyor 1010 may be
positioned at a higher elevation than the second longitudinal conveyor
1030. After one chord portion 200 advances along the second longitudinal
conveyor 1030 away from the kickoff position 1060, another chord portion
may be transferred from the lateral conveyor 1020 to the second
longitudinal conveyor so that chord portions 200 are queued along the
second longitudinal conveyor.

[0085]The chord portion 200 travels along the second longitudinal conveyor
1030 in the longitudinal direction 50 and stops beneath the rigging table
1000 in the truss assembly area 1070 to be used in the assembly of a
truss on the rigging table 1000. The material handling apparatus and the
process of providing chord portions 200 from a material rack 1050 to the
truss assembly area 1070 beneath the rigging table 1000 on the second
longitudinal conveyor 1030 is duplicated on the opposite side of the
rigging table 1000. In this manner, chord portions 200 are automatically
fed to the truss assembly area 1070 beneath the rigging table 1000 on
both sides of the rigging table 1000 as shown in FIG. 12.

[0086]FIG. 13 is a schematic diagram of a side view of an exemplary
embodiment of a portion of the rigging table 1000 of FIG. 12 illustrating
the relationship between the second longitudinal conveyor 1030, a worker
guard panel 1110, and automated chord portion lifting arms 1120. The
worker guard panels 1110 protect the operators, or riggers, on either
side of the rigging table 1000 from the mechanism of the conveyor 1030.
The worker guard panels 1110 are capable of moving to enable the chord
portion to be moved from beneath the bunk assemblies to above the bunk
assemblies for positioning for assembly of a truss, and moving back to
facilitate movement of workers adjacent the lateral extent of the base. A
plurality of automated lifting arms 1120 may be positioned along the
rigging table and are capable of automatically extending to lift a chord
portion 200 off of the conveyor 1030 upward toward the base 600 of the
rigging table 1000 when the guard panels 1110 are in an open position.
The extended lifting arms 1120 may position the chord portions between
the riggers and the rigging table enabling the riggers to lift and move
the chord portions onto the frame 30 and guides 60 for assembly of a
truss. The automated lifting arms 1120 present a chord member when the
guard panels 1110 are in the open position. The guard panels may be
segmented between lifting arms 1120, or include apertures at each lifting
arm, such that the guard panels may return to a closed position with the
lifting arms 1120 in the extended position.

[0087]FIG. 14A is a schematic diagram of an end view of a portion of the
rigging table 1000 of FIG. 13 showing a chord portion 200 resting on the
chord portion conveyor 1030 with the worker guard panel 1110 in the
closed position and the automated lifting arms 1120 in a retracted
position. FIG. 14B is a schematic diagram of an end view of a portion of
the rigging table 1000 of FIG. 13 showing the chord portion 200 lifted
off of the chord portion conveyor 1030 by the automated lifting arms 1120
with the worker guard panel 1110 in the open position.

[0088]The top portion of each lifting arm 1120 may be L-shaped in order to
snag or catch the chord portion 200 in the L-shaped top portion and lift
the chord portion 200 off of the conveyor 1030. When extended, the arms
1120 may be about the height of the bunk assembly. Once the arms 1120 are
extended with a chord portion 200 in the L-shaped top portion, the guard
panels 1110 may be closed (retracted), leaving the arms 1120 extended
through the apertures in the panel, so that the operators can approach
the chord portion 200, grab the chord portion 200 off the arms 1120, and
place the chord portion 200 onto the bunk assemblies. There may be at
least one operator positioned on each side of the bunk assembly. The arms
1120 then retract after the chord portion 200 is lifted from the arms
1120 by the operators. In response to the arms 1120 retracting, the
second longitudinal conveyor 1030 may present another chord portion 200
under the base 600 of the rigging table 1000 in preparation for
presenting the next chord portion. This process occurs on both sides of
the rigging table 1000.

[0089]When a chord portion 200 is lifted upward off of the conveyor 1030
by the lifting arms 1120, the operators may lift the chord portion 200
and place the chord portion 200 onto the nesting portion 73 of the bunk
assemblies 10 and 800, for example. FIG. 15 illustrates an exemplary
embodiment of an automated lifting arm 1120 in an extended position for
lifting a chord portion 200 upward off of a chord portion conveyor 1030.
FIG. 16 illustrates an exemplary embodiment of an automated lifting arm
1120 in a retracted position before lifting a chord portion 200 from the
chord portion conveyor 1030.

[0090]A controller is provided capable of receiving inputs from the
riggers and activating the rigging table in a desired sequence. The
controller may include a computer-based platform such as, for example, a
personal computer (PC) or the controller may include a programmable logic
controller (PLC), for example. The controller interfaces to the material
handling apparatus and the rigging table such that the controller may
activate/deactivate various actuators of the material handling apparatus
and the rigging table in order to control the flow of material (i.e.,
chord portions) and in order to control various actuating features of the
rigging table. The controller may include a user interface (e.g., a touch
screen) enabling a lead operator to manually select various functions to
initiate various control commands to the material handling apparatus
and/or rigging table.

[0091]Sensors (not shown) may be provided to indicate the position of
chord portions 200 in the material handling apparatus, for example, the
presence of a chord portion 200 in the truss assembly area 1070, and
capable of providing corresponding signals to the controller. Further,
sensors may be provided to indicate the position of portions of the
rigging table, for example, clamp arms 80, guard panels 1110, lifting
arms 1120, and other portions of the rigging table and providing signals
corresponding to the position to the controller. The controller may
further be capable of receiving signals from the sensors and activating
the rigging table in response to the sensor signals.

[0092]For example, during operation, after a truss is assembled on the
rigging table 1000 (e.g., tack-welded), the assembled truss may be lifted
and tilted upward to be rolled off of the rigging table 1000 as
previously described herein, in response to commands from the controller.
The actuation of the release members 100 lifting up the assembled truss
may automatically signal the controller to actuate the transfer of a
chord portion 200 from the lateral conveyor 1020 to the second
longitudinal conveyor 1030 on both sides of the rigging table 1000. When
it is time to present a next chord portion 200 to the operators, the
controller may command the actuation of the guard panels 1110 such that
the guard panels move into the open position to allow a chord portion to
be extended. The guard panel 1110 may move downward like a hinged door,
may move laterally, translate downwardly, or otherwise move into the open
position. The lifting arm apertures in the guard panels 1110 may have a
cut-out or open area that begins below the conveyor 1030 and extends
upward such that the lifting arms 1120 may pass through when the guard
panels 1110 are opened, and the lifting arms may remain extended when the
guard panels are closed.

[0093]When using the rigging table 1000 to assemble a truss, operators
place bottom chord portions 200 onto the bunk assemblies and set webs 500
across the bottom chord portions. The webs may be tack-welded to the
bottom chord portions. Then, a top chord portion may be lifted up and
placed by the operators on top of the webs. Each operator may activate an
automated clamp member 20 to close the clamp arm 80 to secure the webs
sandwiched between the top and bottom chord portions at each clamping
position. The top chord portion may then be tack-welded to the webs. A
lead operator may then activate a global release of all the clamp arms
80, via the controller, which retracts all of the clamp arms 80 an
initiates lifting of the resultant assembled truss.

[0094]While certain embodiments have been described in the present
application, it will be understood by those skilled in the art that
various changes may be made and equivalents may be substituted without
departing from the scope of the claimed invention. In addition, many
modifications may be made to adapt a particular situation or material to
the teachings of the claimed invention without departing from its scope.
Therefore, it is intended that the claimed invention not be limited to
the particular embodiments disclosed, but that the claimed invention will
include all embodiments falling within the scope of the appended claims.